Proteorhodopsins in Southern Ocean Bacteria

Metadata record for data from AAS Project 3127See the link below for public details on this project.Bacteria in marine environments have been found to be able to partially support growth by using light to generate energy in a non-photosynthetic process. This is possible due to a special protein called proteorhodopsin. It is hypothesised that formation of proteorhodopsin has evolved to cope with extreme lack of nutrients. The goal is to determine the significance of proteorhodopsins in the productivity of Southern Ocean microbial communities. This includes determination of proteorhodopsin distribution, presence in seawater and sea-ice samples using molecular techniques, and determination of how important environmental factors (light, nutrient availability, temperature) may drive its synthesis and activity. Taken from the 2009-2010 Progress ReportProject objectives:1. Determine incidence of proteorhodopsins in Southern Ocean water and sea-ice derived bacteria (Year 1) and other Antarctic aquatic environments (Year 2 and 3).2. Determine whether proteorhodopsins contribute to food web energy budgets.3. Determine how proteorhodopsin contributions are influenced by physicochemical features of the environment including light availability, temperature and nutrients. Progress against objectives:Proteorhodopsin is a light harvesting membrane protein that has been found recently to occur in 30-70% of marine bacterial cells. The role of this protein is uncertain but believed to be highly important in energy and nutrient budgets in food webs as it is capable of generating a proton gradient. Amongst a cultured set of Antarctic bacteria we have discovered many PR-producing species. These include many Antarctic lake species. Research is ongoing to determine affect of light on the physiology of these bacteria in particular the genome sequenced species Psychroflexus torquis, an extremely cold-adapted resident of Antarctic sea-ice. 1. Completed screen of Antarctic bacterial collection for proteorhodopsin (PR) genes using PCR-based approaches2. Proteomic-based analysis of PR-bearing sea-ice species Psychroflexus torquis is currently ongoing3. Light/dark defined growth-based experiments determining conditions leading to biomass enhancement are ongoing

本数据集的元数据记录来自AAS 3127号项目，项目公开详情可通过下方链接查阅。
研究表明，海洋环境中的细菌可通过非光合过程利用光能合成能量，以此部分维持自身生长。该过程依赖于一类名为菌视紫红质（proteorhodopsin）的特殊蛋白质。有假说提出，菌视紫红质的演化形成是为了应对极端营养匮乏的环境。本项目的核心目标是探明菌视紫红质在南大洋微生物群落生产力中的重要意义，具体包括：采用分子技术检测菌视紫红质的分布特征，及其在海水与海冰样本中的存在情况；同时明确光照、营养可利用性、温度等环境因子对其合成与活性的调控作用。本内容节选自2009-2010年度项目进展报告。

项目目标：
1. 检测南大洋水体及海冰来源细菌（第1年）与其他南极水生环境（第2、3年）中菌视紫红质的检出率。
2. 探明菌视紫红质是否对食物网能量预算存在贡献。
3. 明确环境理化因子（包括光照可利用性、温度与营养水平）如何影响菌视紫红质的功能贡献。

项目目标完成进展：
菌视紫红质是一类光捕获膜蛋白，近期研究发现其在30%~70%的海洋细菌细胞中均可检测到。该蛋白的具体功能尚未完全明确，但据信对食物网的能量与营养预算至关重要，因其能够介导质子梯度的形成。在已分离培养的南极细菌菌株中，我们已发现多种可产生菌视紫红质的物种，其中涵盖诸多南极湖泊特有菌种。目前相关研究仍在推进中，旨在探明光照对这类细菌生理特性的影响，尤其是全基因组已完成测序的极寒适应海冰常驻物种Psychroflexus torquis。
1. 已采用基于聚合酶链式反应（PCR）的方法，完成南极细菌菌株库中菌视紫红质（PR）基因的筛选工作。
2. 目前正在对携带菌视紫红质的海冰物种Psychroflexus torquis开展蛋白质组学分析。
3. 旨在明确可促进菌体生物量提升的光照/黑暗培养条件的生长实验仍在进行中。